Upconversion luminescence and mechanisms in Yb3+-sensitized Tm3+-doped oxyhalide tellurite glasses

Effect of Yb2O3 content on upconversion luminescence and mechanisms in Yb3+-sensitized Tm3+-doped oxyhalide tellurite glasses were investigated under 980 nm excitation. Intense blue and relatively weak red upconversion emission centered at 476 and 649nm corresponding to the transitions (1)G(4) -> H-3(6) and (1)G(4) -> H-3(4) of Tm3+, respectively, are simultaneously observed at room temperature. The results show that upconversion blue and red emission intensities of Tm3+ first increase, reach its maximum at Yb2O3% = 3 mol%, and then decrease with increasing Yb2O3 content. The effect of Yb2O3 content on upconversion intensity is discussed, and possible effect mechanisms are evaluated. The investigated results were conducing to increase upconversion luminescence efficiency of Tm3+. (c) 2005 Elsevier B.V. All rights reserved.

Comparative investigation of up-conversion luminescence in Tm3+-doped oxide-chloride germanate and tellurite glasses

Tm3+-doped oxide-chloride germanate and tellurite glasses have been synthesized by conventional melting method. Intense up-conversion luminescence emissions were simultaneously observed at room temperature in these glasses. The possible up-conversion mechanisms are discussed and estimated. However, in these Tm3+-doped glasses, tellurite glass showed weaker up-conversion emissions than germanate glass, which is inconsistent with the prediction from the difference of maximum phonon energy between tellurite and germanate glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Our results confirm that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. (c) 2005 Elsevier Ltd. All rights reserved.

Frequency upconversion properties of Tm3+ doped TeO2-ZnO glasses containing silver nanoparticles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the heat treatment on the nucleation of silver nanoparticles in Tm3+ doped PbO-GeO2 glasses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tm3+ and Tm3+-Ho3+ doped fluorogermanate glasses for S-band amplifiers

Two series of glasses with composition (mol%) 70PbGeO3- 15PbF2-15CdF2, the first one with different Tm 3+ contents (0.2, 0.4, 0.6 and 0.8 mol%) and the second one with 0.2 mol% Tm3+ and different Ho3+ contents (0.1, 0.5, 1.0 and 1.5 mol%), have been prepared and some of their spectroscopic properties studied. Absorption in the visible-near infrared and emission in the near infrared region of the electromagnetic spectrum have been obtained. Concerning emission at the 1.4-1.5 μm region, optimization of rare earth ions content leads to 0.2 and 0.5 mol% for Tm3+ and Ho3+, respectively. We discuss potential application of these compositions. © 2005 Elsevier B.V. All rights reserved.

Frequency upconversion properties of Tm3+ doped TeO2-ZnO glasses containing silver nanoparticles

Frequency upconversion (UC) properties of Tm3+ doped TeO2-ZnO glasses containing silver nanoparticles (NPs) were investigated. Infrared-to-visible and infrared-to-infrared UC processes associated to the Tm3+ ions were studied by exciting the samples with a cw 1050 nm ytterbium laser. The luminescence intensity as a function of laser intensity was also measured using a pulsed 1047 nm Nd3+:YVO laser in order to determine the number of photons participating in the UC processes. Enhancement of the UC signals for samples heat-treated during various time intervals is attributed to the growth of the local field in the vicinity of the NPs. PL enhancement by one-order of magnitude was observed in the whole spectrum of the samples heat-treated during 48 h. On the other hand PL quenching was observed for the samples heat-treated more than 48 h. (c) 2011 Elsevier B.V. All rights reserved.